Henry Spencer <henry@zoo.toronto.edu> writes:
|> When people first started implementing profilers and the like, they found
|> one striking result: human intuition about the locations of the hot spots
|> in a complex program was *consistently wrong*. ...
|>

To be worthwhile, any compiler which accepts user hints like frequency or
register has to have the following property:

A correct hint must make an improvement that is worth gathering the
information, and an incorrect hint must either be detectable or must not
reduce performance much.